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A multilevel inverter topology is designed which is capable of generating 24 sided (icosikaitetragonal) voltage space vectors. The proposed converter can be used as an induction motor drive, but the motor should be an open ended induction motor. In an open ended induction motor all the six ends of the induction motor stator windings are used for feeding electric power. The structure of this inverter...
The demand of energy is increasing day by day and the fossil fuels are moving towards the end. There comes the portance of non-ending sources like wind energy. The proposed system is a wind energy conversion system consisting of Z source inverter(ZSI). Z source inverter is the one which can invert DC and buck boost operation is also possible. It carries more advantages than conventional buck boost...
Conventional power generators are fueled by natural gas, steam, or water flow. These generators can respond to load changes by varying the fuel input by a valve control. Renewable power generators such as wind or solar, however, are not controllable since their fuel sources are intermittent in nature. This creates difficulties for planning generation systems having renewable energy sources. A methodology...
Adopting MPC to a fast changing system has always been a challenging problem due to the computational efficiency. As the equivalent aggregation strategy and the fast algorithm based on MPC proposed, the computational efficiency has been promoted greatly. This paper improves the fast algorithm combined with the equivalent aggregation strategy, and investigates the feasibility of adopting the fast algorithm...
In this paper, the application of adjustable angle ds-qs axis transformation for three-phase current source induction motor drive is proposed. In order to reduce higher switching number caused by ignoring induction motor back-EMF, the ds-qs axis transformation with regulating angle technology is applied to motor drive. Using hysteresis current controller and voltage space vector, the status of switches...
Common-mode voltage (CMV) is responsible for overvoltage stress to the winding insulation and bearing damage of an AC motor. High dv/dt of CMV causes leakage currents, which create noise problems to the equipments installed near the converter. This paper proposes modulation strategy for three-level T-type NPC that substantially eliminates CMV. The principles of selecting suitable triangle carrier...
The efficiency is the important factor for the power converter that is used in photovoltaic application. This paper proposes a new SVPWM method for three - level TNPC topology to improve the efficiency by minimize the number of switching. The proposed method is based on the virtual flux vector. By applying proper non-zero voltage vectors, a quasi circle will be created. The performance of the converter...
This paper proposes the modified SVPWM control algorithm for the three-phase voltage source inverter, which consists of traditional six switches voltage source inverter and three bidirectional switches for creating the ac decoupling circuit. This topology has the advantages such as the ability to reduce the overall power losses in inverter system and beside that, to decrease the leakage ground current...
The direct torque control of induction motor has good dynamic performance of torque and flux. However, the switching frequency (in the case of conventional DTC) is variable and difficult to control due to the use of hysteresis controllers. This lack of control over frequency is the origin of torque and flux ripples. Similarly, the use of a voltage inverter with two levels limits the power of the drive...
Multiphase drives are now becoming serious competitor to traditional three-phase drives due to reasons of better fault tolerant property and reduced per-phase converter rating that are especially suited to high power drives application. One of the major factor of widespread research on multiphase drive are the availability of high computational power of control platforms such as DSP and FPGAs. With...
This paper presents a design of a digital direct power control strategy for a three-phase grid-connected inverter combining the discrete-time sliding mode control and the space vector modulation. Using the discrete-time state-space model of the controlled system, a discrete-time sliding mode control system is designed. Its output is a control vector which minimizes the instantaneous active and reactive...
In this work a multilevel inverter based grid connected photovoltaic system is presented. It is used a T-type multilevel inverter. This inverter is based on a classic three-phase voltage source inverter. However, in order to increase the number of voltage levels, three extra bi-directional switches are used. These switches are connected between the three-phase terminals of the inverter and a common...
In this paper, we present closed loop sampled-data linear quadratic regulator (LQR) based control scheme. Suggested scheme is applied on a practical linear system of a grid tie inverter for tracking a reference signal in the presence of external disturbance. LQR functions on the basis of minimization of a well-defined cost function. Prior knowledge about the external disturbance is utilized by the...
Distributed Resources in the Smart Grid, such as Distributed Generation (DG) and Responsive Loads (RL) are capable of providing a wide range of ancilliary services, if properly coordinated. However, because of their large numbers and distributed nature, using a fully centralized communication structure to achieve coordination can be prohibitive, due to scale and cost. Decentralized approaches based...
This paper proposes an independent control of two induction motors fed nine switches inverter. In this context, an adaptive direct torque control is developed to ensure the separate control of the both induction motors. Simulations are carried-out on induction motors, to show that the developed independent control is effective and provides a simple configuration with high performance in terms of speed...
Due to control simplicity and easy applicability DTC has become popular and adopted in many industrial applications. But it still suffers from a few drawbacks like- comparatively large torque ripple in a low speed range and its performance is highly depended on speed of the motor and hysteresis bands of torque and flux ripple. To address these problems, this paper represents a direct torque control...
In order to get better performance at different speed regions in Direct Torque Control (DTC) for induction motor system, a speed adaptive strategy combining two control models are established—hexagon flux linkage control model and SVM-DTC control model. The new method takes full advantage of two models and makes a transition between them according to rotor speed. According to the result analysis and...
In this paper, the operation characteristics of five-level active-neutral-point-clamped (5L-ANPC) inverters under device short failure conditions are analyzed. A new fault tolerant control scheme is proposed, which enables continuous operation and generating three-phase sinusoidal currents of 5L-ANPC inverters. The remaining redundant voltage vectors can still be utilized to improve operating performance...
In this paper, a 5th and 7th harmonic suppression technique for a 2-level VSI fed IM drive, by using capacitive filtering is proposed. A capacitor fed 2-level inverter is used on an open-end winding induction motor to suppress all 5th and 7th order harmonics. A PWM scheme that maintains the capacitor voltage, while suppressing the harmonics is also proposed. The proposed scheme is valid for the entire...
In this paper we investigate the use of distributed PI actions to achieve consensus and synchronization in complex networks. We show that by extending the classical linear diffusive coupling with an integral action it is possible to achieve better performance and steady-state behavior than with more traditional strategies. After briefly summarizing the theoretical results, we investigate the viability...
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